Thomas precession as a source of the electromagnetic angular momentum radiation

Using the general principles of the relativistic radiation theory two alternative definitions of the angular momentum density of the electromagnetic field by Ivanenko-Sokolov and by Teitelboim are discussed. It is shown that both definitions give identical integral characteristics of radiation for an arbitrary moving relativistic charge. It is obtained that the total power of the field spin angular momentum radiation is proportional to the Thomas precession and corresponds to the force field momentum of radiation. As an application there are considered properties of the orbital and spin moments of the synchrotron radiation.